Turbo-machines normally have two-part rotationally symmetrical vane carriers which are mechanically connected at their largest diameters--and only there--to the lower casing part and the upper casing part. The connection between the vane carrier and the turbine casing can be produced either by a flange of the turbine casing engaging in a corresponding annular groove of the vane carrier or by a collar of the vane carrier engaging in a corresponding annular groove in the upper casing part and in the lower casing part. The turbine upper casing part extends in the axial direction from the largest diameter of the vane carrier to the compressor part of the turbine. A flange of the upper casing part makes contact with a corresponding flange of the compressor part and the two flanges are mechanically connected.
The upper casing part is supported on the lower casing part of the turbine in the horizontal plane through the turbine axis. The mechanical connection of the upper casing part to the vane carrier, on the one hand, and to the compressor part, on the other, is so dimensioned that it can satisfactorily deal with the high gas pressure within the turbine. This requires close dimensional tolerancing of the components quoted above. In addition, however, a clearance fit has to be provided between the upper casing part and the vane carrier and between the upper casing part and the compressor part, in order:
to facilitate assembly and dismantling of the turbine,
to make sufficient allowance for the material expansions in the flange areas, arising due to thermal effects.
For the reasons given above, turbines normally have adjustment devices which are used, during dismantling, to provide variable clearance fits at the connection points between the turbine upper casing part and the vane carrier and, during assembly, to provide a mechanically fixed connection between the upper casing part and the vane carrier.
One known externally adjustable axial location is, for example, provided by means of an axially adjustable pin which can be adjusted by the use of an eccentric sleeve and which engages in a recess in the vane carrier.
In order to completely utilise the adjustment force, the known adjustment device must be located in the upper part of the turbine between the vane carrier fastening and the combustion chamber stub pipes. The space available, however, is very limited in this region. A feature of this adjustment device is, moreover, that it demands a relatively large amount of space and is associated with an additional accumulation of the volume of cast material in order adequately to dimension and locate all the necessary components. The region in which this adjustment device is located is subject to powerful thermal loads, and material deformations can occur due to widely varying wall thicknesses in the upper casing part.